Field of the Invention
The invention relates to a method for indicating temperatures and, more particularly, to a method for displaying different temperatures by a thermometer and the thermometer using the method.
Description of the Related Art
In a thermometer, a temperature sensor is used to transmit electrical signals, and then a measured or predicted temperature value is displayed on a display screen (such as a liquid crystal display, a digitron display, or an LED array display and so on) in a numerical mode. With the advantages of ease of temperature value reading, shorter measuring time, higher measuring precision, available memory, and buzzing warning, the thermometer gradually replaces the conventional mercury-in-glass thermometer and is widely applied in many occasions such as home or hospital.
Although the thermometer can display the temperature value of a measured human body, a user must remember temperature critical values for dividing three different states: normal state, low fever state, and high fever state, thus to determine whether the human body needs medical treatment. In addition, while the temperature value can be read more easily via the thermometer than the mercury-in-glass thermometer, the temperature value reading is very difficult for people with poor eyesight, particularly for presbyopic elderly people. Therefore, there is short of a thermometer capable of effectively and intuitively reflecting whether the measured human body runs a fever thus to determine whether the medical treatment is needed.
At present, there is a kind of thermometer on the market capable of displaying different states of normal, low fever, and high fever by changing colors of the backlight of the display screen. In detail, the thermometer has two or two groups of LED lamps (one emits green light, and the other emits red light) in a backlight module and additionally has circuits for control, thus to allow the two LED lamps to light singly or together. When the green LED lamp is lit, the display screen displays green color, showing a normal state. When the red LED lamp is lit, the display screen displays red color, showing a high fever state. When the two LED lamps are lit together, the display screen displays yellow color, showing a low fever state. The thermometer intuitively reflects whether the temperature of the measured human body is normal and different fever states by the above-mentioned method.
However, since at least two LED lamps are used as the backlight in this kind of thermometer, the service life thereof is very limit. After the thermometer is used for a period of time, the brightness of the LED lamp may decrease. Particularly, when the color of one LED lamp fades out, the user may be confused about the state displayed by the thermometer, which may cause the user to make a misjudgment and even cause delay of the treatment to the patient. For example, when the LED lamps with two colors are lit together, and the brightness of the green LED lamp apparently decreases due to frequently lightening, the displayed color of the display screen will be partial to the red color, which may cause the user to make a misjudgment and think that the present measured human body runs a high fever.
In addition, compared with other thermometers, this kind of thermometer needs to additionally include the LED lamps in structure. Further, driving circuits are needed to be separately disposed on the circuit to control the two LED lamps to light singly or together, thereby allowing the producing technology to be more complicated and improving the manufacturing cost of the thermometer.